1. Field of the Invention
The present invention relates to a latch device for a tailgate of a vehicle.
2. Description of the Related Art
Japanese Patent Publication No. 5-45753 describes a latch device arrangement used in a vehicle tailgate having an upper door and a lower door which are respectively rotatably attached to the rear surface of a vehicle body. The latch device arrangement comprises: a lower striker fixed to the vehicle body (A); a lower latch assembly (E) attached to the lower door (D) for holding the lower door (D) in a door-closed position by engaging with the lower striker; an upper striker (54) fixed to the upper door (C); an upper latch assembly (F) attached to the lower door (D) for holding the upper door (C) in a door-closed position by engaging with the upper striker (54); an open handle assembly (30) attached to the lower door (D) and operatively connected to the lower latch assembly (E) for releasing an engagement between the lower latch assembly (E) and the lower striker to open the lower door (D) when operated; opening means (36) attached to the lower door (D) and operatively connected to the upper latch assembly (F) for releasing an engagement between the upper latch assembly (F) and the upper striker (54) to open the upper door (D) when operated; and a coupling mechanism (H) displaceable between a locked position for disabling a door opening operation of the open handle assembly (30) and an unlocked position for enabling the door opening operation of the open handle assembly (30). The upper latch assembly (F) has a latch (64) which is displaceable between a door-closed position for engaging with the upper striker (54) and a door-open position for disengaging from the upper striker (54), and a ratchet (66) which is displaceable between an engaging position for engaging with the latch (64) located in the door-closed position so as to hold an engagement between the latch (64) and the upper striker (54) and an initial position for making contact with the latch (64) located in the door-open position. The coupling mechanism (H) is displaced to the locked position when the upper door C) is closed and displaced to the unlocked position when the upper door (C) is opened.
A first disadvantage of the prior art device is in that detecting means for detecting the position of the upper door (C) is complex. That is, the prior art detecting means is composed of a sliding member (90) which is slid by engaging with a base plate (56A) of the upper striker (54) when the upper door (C) is closed, and a rotating lever (24) which displaces the coupling mechanism (H) to the locked position when rotated by the movement of the sliding member (90). Further, if the mounting positions of the three members (54), (56A) and (90) are not accurate, it becomes difficult to accurately detect the position of the upper door (C).
Moreover, since the coupling mechanism (H) of the prior art device is attached to a bracket (12) which is fixed to the lower door (D), the connection of the coupling mechanism (H) and the open handle assembly (30) is troublesome. Furthermore, since the coupling mechanism (H) has a lever (10) which is supported by a longitudinal shaft (12A) and a lever (23) which is supported by a lateral shaft (21), it becomes large in both longitudinal and lateral directions.